TSV Die Loop-Back Testing via Substrate Carrier Through-Holes
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Solution Overview
Problem
The existing PoP assembly process for TSV-containing ICs faces electrical testing challenges due to the presence of the substrate carrier, which blocks access to the frontside of the TSV die, leading to potential TSV formation, contact, and shorts issues that can only be detected after the top die is assembled, resulting in failed PoP testing.
Innovation Solution
Incorporating through-holes in the substrate carrier aligned with BGA pads to allow probe contact to the frontside of the TSV die and using a topside coupler with matching coupling terminals and lateral connection circuitry to create TSV loop back paths for electrical testing, enabling contact with contactable TSV tips on the bottomside of the TSV die while the carrier is present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate carrier is used to provide rigidity during PoP assembly, then structural stability is improved, but access to the frontside of the TSV die is blocked preventing electrical testing
Solution Approach 1:
The substrate carrier is segmented with through-holes that allow probe access to the frontside of the TSV die while maintaining structural integrity. This segmentation enables both structural stability and electrical testing accessibility simultaneously.
Solution Approach 2:
The through-holes in the substrate carrier act as intermediaries, allowing probe needles to reach the frontside of the TSV die without removing the carrier. This mediator approach enables electrical testing while the carrier remains in place to provide structural support.
2Ease of manufacture
If the TSV die is thinned to expose TSV tips for customer assembly, then manufacturability is improved, but electrical defects cannot be detected before shipping
Solution Approach 1:
Electrical testing is performed preliminarily on the thinned TSV die while it is still attached to the substrate carrier with accessible frontside. This preliminary action detects electrical defects before the die is shipped to the customer, maintaining both manufacturability and reliability.
Solution Approach 2:
The testing system uses the existing substrate carrier structure and through-holes to enable self-testing of the TSV die without requiring removal from the carrier or additional complex equipment. The system serves itself by utilizing available resources.
3Productivity
If wafer probe testing is omitted after die attach, then productivity is improved, but defective PoP precursors are shipped resulting in final PoP testing failures
Solution Approach 1:
The mechanical wafer probe testing process is replaced with an electrical testing method that uses probe needles through substrate carrier holes to contact the frontside of the TSV die. This substitution maintains productivity while improving reliability by enabling defect detection.
Data Source
AI summary
A method of testing electronic assemblies including singulated TSV die attached to a ML package substrate, on a substrate carrier. The substrate carrier includes through-holes for allowing probe contact to the BGA substrate pads on a bottomside of the package substrate that are coupled to the frontside of the TSVs. Contactable TSV tips on the bottomside of the TSV die are contacted with a topside coupler that includes a pattern of coupling terminals that matches a layout of at least a portion of the TSV tips or pads coupled to the TSV tips. The topside coupler electrically connects pairs of coupling terminals to provide a plurality of TSV loop back paths. The BGA substrate pads are contacted with a plurality of probes tips that extend through the through-holes to couple to the frontside of the TSVs. Electrical testing is performed across the electronic assembly to obtain at least one test parameter.